Articles such as disposable absorbent garments have numerous applications including diapers, training pants, feminine care products, and adult incontinence products. A typical disposable absorbent garment is formed as a composite structure including an absorbent assembly disposed between a liquid permeable body side liner and a liquid impermeable outer cover. These components can be combined with other materials and features such as elastic materials and containment structures to form a product which is specifically suited to its intended purposes. A number of such garments include fastening components which are intended to be connected together (e.g., pre-fastened) during manufacture of the garment so that the product is packaged in its fully assembled form.
For example, one such pre-fastened garment includes child's training pants, which have a central absorbent chassis and front and back side panels extending laterally out from the chassis adjacent longitudinally opposite ends thereof. A portion of each of the front and back side panels has a respective fastening component disposed thereon. During manufacture of the training pants, the central absorbent chassis is initially formed generally flat and then folded over so that the front and back side panels face each other. The respective fastening components of the front and back side panels are then aligned and connected together to define an engagement seam. Upon securing the front and back side panel fastening components together, the pre-fastened pair of training pants is in its fully assembled three-dimensional form having an interior space bounded in part by the engagement seam.
For a variety of purposes, including quality control, process control, material control, and so on, it is often desirable to monitor the presence of and/or interrelationships between one or more elements of a disposable absorbent garment. For instance, elements such as outer covers, liners, absorbent pads, side panels, elastic components, fastener components, etc. must be positioned or aligned with respect to each other and/or to other components as desired or otherwise intended in order to produce an acceptable product. Accordingly, inspection systems are commonly used to detect the presence and/or relative positions of such components during manufacturing. If an inspection system determines that one or more components are out of position and thus do not properly register with other components, the inspection system typically outputs one or more signals indicating that certain articles should be culled and discarded, that the process should be adjusted so as to bring out-of-position components into proper position, that the process should be adjusted so that subsequent components are brought into proper registration with one another, and so on.
One such registration inspection system is disclosed in U.S. Pat. No. 5,359,525, the disclosure of which is incorporated herein by reference. As described therein, registration inspection of a composite product during fabrication is accomplished by producing an image of the article and then analyzing the image to detect the relative positions of one or more components. The detected positions are then compared to desired positions to thereby determine whether one or more components are improperly positioned. Such registration inspection systems employ conventional video cameras for capturing visible, ultraviolet, x-ray, and infrared light reflected by and/or transmitted through components of the product in order to produce still video images of such components. Thus, after producing a video image of a composite article and its several components, the image can be analyzed to determine whether the components are properly positioned and registered with one another.
Although highly useful for many applications, there is a need for a higher order level of inspection and control that provides advantages with respect to the inspection, analysis and control of high speed web converting processes associated with manufacturing products having tight quality tolerances. Such products include, for example, certain products having engagement seams formed by connecting two elements together such that the engagement seam is essentially two layers. For example, engagement seams formed by connected side panels of the training pants described previously has heretofore entailed connecting the side panels in face-to-face relationships with outer edges of the side panels aligned with each other. To inspect such an engagement seam, it was necessary only to inspect the exposed outer edges of the side panels so that there was no need to actually capture an image of any underlying elements or edges of the training pants. More recent engagement seams, however, are formed by connecting the side panels in overlapping relationship so that the outer edge of one side panel underlies the other side panel at the engagement seam. Still referring to the engagement seam example, arriving at a finished state of properly engaged side seams requires a precise final positioning of the edges of the fastening system components on the side panels. Such a level of control can be accomplished through a cascaded process control of multiple (e.g., up to seven in one example) dependent product geometrical relationships that can be affected by material, process settings, process set points, transient conditions, and so on.
It is desirable to capture an image of the underlying panel at the engagement seam to determine the position and relative alignment of the outer edge of the underlying panel. Because the light emitting source and camera of the inspection system described in U.S. Pat. No. 5,359,525 are positioned exterior of the inspected component, it is difficult to inspect the outer edge of an underlying panel of the more recent engagement seams once the panels are connected. For example, it is difficult to lay the engagement seam flat over the light emitting source of the disclosed inspection system, thereby increasing the risk that the image captured by the camera will appear fuzzy. Moreover, it is difficult for the visible or ultraviolet light to pass through or reflect from the underlying layer of the multiple layers present at such an engagement seam.
Moreover, prior art systems for inspecting composite articles, such as, for example, disposable absorbent garments, do not integrate and relate data from multiple inspection stations to prioritize necessary or desirable automatic control actions, trouble-shooting actions/recommendations, operator alarming, and so on.
Further, prior art systems for inspecting composite articles, such as disposable absorbent garments, did not integrate and relate information/data from multiple inspections systems with information from other information systems associated with a manufacturing process. For example, database systems have been employed for collecting waste/delay/productivity information, raw material information, manually entered quality information (e.g., from manual inspections of selected items), and machine process information. In fabricating articles such as diapers and training pants, such information includes productivity associated with a particular production run, various attributes of the raw materials used, process control settings (e.g., vacuum settings, machine set points, conveyor steering commands, and so on), and the like. Such prior art information, however, has not been correlated to inspection information so that improvements can be made, for example, to further reduce cost and waste, and to increase productivity and quality.
Improvements are also desired with respect to information systems associated with web converting processes. For example, web converting manufacturing processes often use multiple station devices, with each station performing a substantially similar function. Prior art information systems do not adequately isolate and exploit inspection data associated with a particular station of such multiple station devices. It has been known to use simple photoeye detectors to detect whether a side panel placed by a multiple station device was present on the absorbent article constructed using that device. Identifying and exploiting additional aspects of multiple station devices, however, is desirable.